For virtually all electronic power processing systems, current sensing is an important and necessary function, it is necessary in any system that provides current limiting or over-current protection. It is also necessary in systems that continually utilize current information to achieve control, such as current mode programming where the current may have a dc component and an ac component which may not necessarily be sinusoidal, and where the instantaneous current, i(t), is to be continually sensed.
Although existing current sensing techniques are generally adequate for conventional applications, the advent of power integrated circuits (PICs) and smart modules has added new requirements not satisfied by conventional current sensing techniques. In particular for PIC applications, the current sensor needs to be monolithic with other power processing and control functions, yet provide an isolated signal of high quality. In the case of smart modules, the current sensor needs to be a two-dimensional element that integrates directly with the conductor structure without impacting mechanical or thermal design considerations. What is needed is a low cost integrated circuit current sensor with isolation, high accuracy and wide bandwidth.